It is rather common to use inhalers for delivering medicaments utilized in the treatment and prophylaxis of respiratory diseases. Inhalation treatment is the most commonly preferred treatment method in these diseases as the inhalers provide ease of use; the medicaments have rapider onset of time resulting from local administration and they have fewer side effects. Various inhalers have been designed in order to provide effective and sufficient delivery of the medicaments used in the treatment of respiratory diseases, particularly in asthma and chronic obstructive pulmonary disease. These inhalers vary according to their operating mechanisms and the physical form of the medicament to be delivered.
In the inhalers used to deliver the medicaments in dry powder form, the medicament is carried in reservoirs, capsules or blisters packages. It is highly significant to deliver each dose to the patient with exact accuracy and preciseness since the required medicament dose in the inhalation is very low.
In general, one blister pocket containing medicament in dry powder form is opened in response to each actuation of the device in inhalers comprising blister packages. One blister pocket containing one dose of dry powder medicament is usually opened by peeling the blister package indexed upon the actuation of the device or piercing the blister pocket by the piercing means in the inhaler. The inhalers comprising peelable blister packs enable the sufficient amount of the dry powder medicament contained in the opened blister to be easily inhaled as the airflow enters the opened blister pocket more easily in the inhalers comprising peelable blister packs than the inhalers comprising pierceable blister packs. Therefore, the blister package should be indexed enough to enable the blister pocket to be opened completely so as to realize an effective inhalation in response to each actuation of the inhaler. However, it is quite difficult to enable the blister package to be indexed properly to the same extent in each actuation of the device so as to realize a safe inhalation in the inhaler comprising peelable blister packages. In the case that the blister package that is indexed upon the actuation of the device is indexed less than the required extent, the blister pocket may not be opened completely while more than one blister pocket may be opened in the case that the blister package is indexed more than the required extent. The fact that one blister pocket cannot be opened completely and an effective inhalation cannot be realized as the sufficient amount of the active agent comprised in the dry powder medicament cannot be delivered to the patient or more than the required amount of the active agent is delivered to the patient as one blister pockets are opened lead to dangerous consequences. Therefore, controlled dosing of the medicament in dry powder form cannot be achieved when the blister package is not indexed properly to the same extent in response to each actuation of the inhaler.
The inhalation device marketed under the trade mark Diskus® by GlaxoSmithKline is one of the most well-known inhalers on the market. This device operates with a slide mechanism and a blister strip package in which the dry powder medicament is carried. However, this device needs to be improved in terms of specifications to enable the blister package to be properly indexed to the same extent in response to each actuation of the device.
The inventor has surprisingly found that the force of attraction imposed by the winding wheel on the lid sheet is balanced, and thus the blister package is properly indexed to the same extent in response to each actuation of the device in the case that each of the preferably polyoxymethylene resilient wings of the winding wheel, on which the lid sheet of the blister package peeled upon the actuation of the inhaler is coiled, is composed of three parts in the inhaler comprising peelable blister package.
To this respect, the present invention relates to an inhaler comprising peelable blister package appropriate for delivering dry powder medicament which enables the blister package to be indexed properly to the same extent in response to each actuation of the inhaler.